v0.5.29

Added

• New MidiButton widget: a pad you press on-screen or bind to a hardware MIDI
  pad. Unlike Knob/Fader (continuous control-change), it learns a MIDI
  note and turns presses into events. mode="momentary" (true while held)
  or mode="toggle" (each press flips value); press_timestamp bumps on every
  press and velocity carries the note-on velocity. Put a built-in icon or any
  emoji/text on the face. MIDI learn is on by default (bindings persist in
  browser localStorage). Demo at demos/midi_button.py.